Efforts to reduce dependence on fossil fuels for transportation fuel and as feedstock for industrial chemicals have been undertaken for decades, with a particular focus on enabling economic feasibility of renewable feedstocks. Heightened efforts are being made to more effectively utilize renewable resources and develop “green” technologies, due to continued long-term increases in the price of fuel, increased environmental concerns, continued issues of geopolitical stability, and renewed concerns for the ultimate depletion of fossil fuels.
Cellulose in biomass is commonly used as a feedstock for biofuel production. For example, cellulose can be used to produce ethanol. Cellulose can also be used to produce furan-based biofuels by way of 5-(halomethyl)furfural, such as 5-(chloromethyl)furfural (CMF). CMF can be converted into 5-(ethoxymethyl)furfural, a compound considered as a promising diesel fuel additive. Alternatively, CMF can also be converted into 5-methylfurfural, another compound considered as a promising a biofuel candidate.
The production of CMF from cellulose was first described in the early 1900s. Currently, various synthetic routes are known in the art to produce CMF from biomass using concentrated hydrochloric acid. For example, U.S. Pat. No. 7,829,732 describes a method of producing CMF from biomass using concentrated hydrochloric acid and 1,2-dichloroethane as a solvent. See also, Szmant & Chundury, J. Chem. Tech. Biotechnol. 1981, 31, 205-212; Liu et al., J. Phys. Chem. A, 2011, 115, 13628-13641. The use of concentrated hydrochloric acid, however, can present several challenges on a commercial scale. For example, use of concentrated hydrochloric acid can cause corrosion of the reactors.
Thus, what is needed in the art are commercially viable methods to produce 5-(halomethyl)furfural from biomass, using lower acid concentrations.